Printer having a selectively variable print font



July 11, 1967 c. c ECKEL 3,330,208

PRINTER HAVING A SELECTIVELY VARIABLE PRINT FONT Filed March 31, 1966 2 heets-Sheet 1 VAV/VAVQV PowZ 70 PA /A17 5,4,

bZZENO/QS 5 @L W a 686 68c 69%; 6. C/(EL BY I I I United States Patent 3,330,208 PRINTER HAVING A SELECTIVELY VARIABLE PRINT FGNT Carl C. Eclrel, Haddon Heights, N.J., assignor to Radio Corporation of America, a corporation of Delaware Filed Mar. 31, 1966, Ser. No. 539,172 Claims. (Cl. 1131-93) This invention relates to printers and, in particular, to a matrix printer of the serial type having provision for varying the print font.

A matrix or facsimile printer is one in which each different character is made up of a distinctive pattern of small picture elements printed at the intersections of selected rows and columns of an imaginary print matrix. In a serial type printer, the picture elements for a character are printed column-by-column serially, and the vari ous characters in a message are printed seriatim along a document print line. These picture elements may be printed by the pressure between selectively energized ones of a group of parallel, independently movable print members and an anvil. Either the anvil or the print members may be moved relative to the other along the document print line to accomplish the column-by-colurnn and character-by-character printing.

It often is desirable to be able to vary the print font so as to be able to print the characters in regular font, bold face or italics. However, as in the case of an onthe-fly electromechanical printer, known matrix printers have no provision for varying the print font.

It is one object of this invention to provide a matrix printer having provisions for varying the print font.

It is another object of this invention to provide a matrix printer having provisions for printing the characters of a particular font in regular form, bold face or italics.

It is still another object of this invention to provide a matrix printer having a variable print font, in which the print font may be varied electronically.

In a serial matrix printer embodying the invention, the selection between regular and bold face printing is achieved by controlling the durations of the actuating signals applied to the print members. Printing of characters in italics is accomplished by delaying, by different amounts, the actuating signals for the different print members.

In the accompanying drawing, like reference characters denote like components, and:

FIGURE 1 is a partial view, in front elevation, of a printer bar assembly and scanning anvil mechanism for a matrix printer;

FIGURE 2 is a block diagram of electronics for operating the printer bar solenoids;

FIGURES 3a, 3b and 3c are views of the letter A printed in regular, italic and and illustrating the printed characters superimposed on an imaginary print matrix;

FIGURE 4 is a drawing, in block form, of the electronics for printing the characters in either regular, italics or bold face; and

FIGURE 5 is a modification of the system of FIGURE 4 for printing in bold face.

In a serial matrix printer, the printer members are located on one side of a document printing zone. An anvil is disposed opposite the printer members on the other side of the print zone, with the document and carbon (or ribbon) interposed between the anvil and the printer members. A column of picture elements for a character is printed by driving selected ones of the printer members against the anvil. In order to print the several columns of picture elements for a character, either the anvil or the printer members are moved relative to bold face, respectively,

the other in a direction along the document print line. A system in which the printer members are movable and the anvil is fixed is illustrated and described in the copending application of Elvin D. Simshauser, Ser. No. 266,548, filed Mar. 20, 1963. In the alternative, a movable anvil may be employed which scans along the print Iine beneath a plurality of parallel, independently actuated print bars. A portion of a system of the latter type is illustrated in FIGURE 1.

In FIGURE 1, a plurality of printer bar structures are stacked parallel to each other, one behind the other, on one side of the document print zone. A portion of the forwardmost printer bar structure 10 is shown in enlarged view in FIGURE 1. This structure 10 comprises first and second elongated, horizontal members 12, 14 which may extend across the width of the carbon and document 16. A plurality of supporting struts 18 are arranged in a regular or repetitive zigzag pattern along the lengths of the elongated members 12, 14 and are joined at their opposite ends to the bottom of member 12 and the top of member 14. These struts 18 maintain the elongated members 12, 14 in spaced, parallel relation, and permit the use of a printer bar structure of thin, lightweight construction.

Printer bar It has a vertically projecting tab 20 at the upper right hand corner thereof. A pivot pin 22 extends through an aperture in tab 20 and is afiixed at its other end to a solenoid link 24, which link is pivotable about a fixed pin 26. A second, vertically projecting tab 30 is pivotable about a pin 32 which, in turn, is connected near the bottom of a link 34. Link 34 is pivotably mounted on a pivot pin 36, which is fixed in space. Link 34 is parallel to the solenoid link 24, and the distance between the pivot pins 32 and 36 is the same as the distance between the pivot pins 22 and 26. Thus, the printer bar structure 10 is suspended on a parallelogram linkage, whereby the bottom printing edge of the lower elongated member 14 is always parallel to the document or paper 16 to be printed. A solenoid 4t has its core 42 adjacent the upper end of the solenoid linkage 24 and spaced slightly therefrom.

The interleaved documents 16 and carbon papers rest upon the upper surface of a platen 44 beneath the printer bars. Platen 44 has a channel or raceway cut in the top thereof into which a moving anvil pin 46 projects. The length of pin 45 is greater than the total thickness of the stacked set of printer bars, and preferably has its top surface even with the top of platen 44 on the other side of the print Zone. This anvil 46 is moved along the raceway beneath the stack of printer bar structures, from one end thereof to the other, by means of a roller cart or carriage 48 which is driven at constant speed on rails 52 by a link chain 59.

The printer bar structures may be very lightweight members. In the de-energized state of the solenoid 40 the printer bar structure it may be free to float on top of the sheaf of documents and carbon papers. No printing takes place at this time because of the very light weight of the printer bar structure, When it is desired to print with this bar 10, solenoid is energized, and attracts the solenoid linkage 24. Linkages 24 and 34 then pivot about the pins 26 and 36, respectively, and drive the printer bar structure 19 in a downward direction to force the lower edge of the printer bar 14 against the anvil 46. This action effects the printing of a mark on the documents at a location immediately above the anvil 46.

As mentioned before, a plurality of printer bar structures are arranged in parallel relation one behind the other. Each bar has associated therewith a separate solenoid which may be energized selectively. For example, there by he a total of nine printer bar structures, which number is sufiicient to print both upper and lower case ing to zone a. Marks then will be printed on the paper a in the first seven rows of the first column or zone of the .print matrix. The solenoids for the first and fifth printer bar structures remain energized as the anvil 46 continues to scan a distance corresponding to the second, third and fourth columns or zones (b, c, d) of the print matrix. The solenoids 40 for the first seven printer bars are energized as the anvil 46 scans across the fifth zone (e) to print the vertical line at the trailing edge of the character. The character thus printed is shown in black in FI .URE 3a.

To accomplish the printing of regular characters in a given font, a system of the type illustrated in FIGURE 2 may be employed. This system may employ a group of clocked gates 69, arranged in seven columns and nine rows, wherein each column corresponds to a difierent zone in the print matrix and each row corresponds to a different printer bar. The information for a character to be printed is supplied in digital form from a character input device 62, the output of which is fed to a decoder 64. The decoder has a plurality of outputs, each of which is energized for a different input character. That output of the decoder 64 which is energized when the character A is to be printed is shown in full in FIGURE 2, and is coupled to the inputs of that pattern of gates 60 which corresponds to the elements of the print matrix for the letter A (FIGURE 3a). These gates are shown shaded in FIGURE 4. The outputs of all of the gates 60 in any one row are connected together and are applied to the solenoid 40 for the respective printer bar.

The selected gates in the encoder 66 are energized or clocked column-by-column timewise to read out the signals to the printer bars column-by-column to print a character. For this purpose, a set of one-shots or monostable circuits 82a, 82b-82g is provided. The output of each oneshot is applied as a clock signal to a different column of gates. When a gate is receiving an energizing signal from the decoder, that gate is partially enabled. When the zone or clock pulse from the one-shot for that column is applied to the gate, the gate transmits an output signal to the associated printer bar solenoid.

Each of these one-shots 82a82g produces a pulse of the same duration, which duration is equal to the time required for the anvil 46 (FIGURE 1) to move a distance equal to one column or zone of the character print matrix (FIGURE 3a). The one-shots are triggered from difierent outputs of a timing network 68a, 68b-68g, which may be a tapped delay line for example. A pulse 74 initiates the sequence of timing pulses. A pulse 74 is generated for each character space, and this pulse may be derived from a timing desk or other pulse generator operated in synchronism with link chain 54) (FIGURE 1). This same pulse, or another pulse derived from the timing mech- :anism, may be employed to gate in a new character to the character input device 62 after the printing of a character.

Alternatively, input device 62 could be, for example, a

shift register which stores, in digital form, the information for an entire print row, and the signals 72 may be applied to advance the information stored in the shift register after a character is printed.

The system as thus far described is capable of printing 7 a fixed font of characters, e.g., letters, numerals, symbols, 1 etc. The font, however, cannot be varied in this system, as

thus described, because of the fixed nature of the decoder 64 and the encoder 60 of FIGURE 2. In some cases, however, it is desired to print the various characters in italics, as illustrated in FIGURE 3b for the letter A, or in bold face, as shown for the character A in FIGURE 30. In a system embodying the invention, the printing of charac- In the FIGURE 4 system an input timing pulse 74 is applied to the timing network 6Sa68g, the same as in the FIGURE 2 system. Similarly, the outputs of the decoder 64 are applied to an encoder 66. The outputs of the encoder are applied, in a manner to be described, to the solenoid coils 79a, Nib-791' of the solenoids for the nine printer bars, respectively. These signals, if necessary, may be amplified in suitable amplifiers 76a, 76b-76i.

The output of each of the zone generating timing members 68a68g is applied to a separate switch arm 78a, 7 Eli-78g. Each switch arm may assume either one of two positions under control of an operator, or under control of a relay solenoid 80, by way of example. When the solenoid St) is in the de-energized state, all of the switch arms 78a-78c are in the upper position and connected to the matrix encoder by way of one-shots or monostable multivibrators 82a, 82b-82g. When solenoid is energized, all of the switch arms 78a-7Sg are pulled in the downward direction, whereby the timing pulses are fed to the matrix encoder by way of one-shots 101a, 101b- 191g.

A set of similar switch arms 86a, 8611-86 appears in the output lines for rows 1 through 8 of the matrix encoder. 'Ihese switch arms also may be hand operated, or else controlled by a relay solenoid 88. In the deenergized condition of solenoid 88, the switch arms 86a- 86h are thrown in the upper positions, whereby the outputs of the encoder for rows 1 through 8 are connected to the amplifiers 76a-76h by way of delay devices a- 9011, respectively. When solenoid 88 is energized, all of the switch arms are thrown to the lower position, and the outputs of the matrix encoder for rows 1 through 8 are connected directly to the inputs of the amplifiers say, one-shots Ski-82g are connected and delay means 9da-9fih are not connected in the system. In that case, the character determined by the output of character input device 62 will be printed in regular form. If the input information represents character A, the printed character will appear in regular form as shown in FIGURE 30.

In the event it is desired to print the character in italic form, solenoid 88 is de-energized, Switch arms 86a-86h then move to the up position, and delay devices 90'a-90h are connected in the output circuitry of the encoder. Each of the delay means 90a90h delays a received signal by a different amount, and the various delays differ according to an arithmetic progression. By way of example only, delay device 90h may be selected to delay thegsignal for a time equal to one-eighth of a zone, i.e., the time it takes the anvil 46 to move a distance corresponding to one-eighth of a zone of the print matrix. Delay means 90g may delay the signal two-eighths of a zone period, and; each of the succeeding delay means 9912-9011 may pro gressively delay the signal for a succeeding multiple of one-eighth of a zone period, whereby delay. means 901; has a full zone period delay. 7

If the character'A is to be printed, for example, the outputs of the matrix encoder 66 are energized simultaneously on rows one through seven during the first zone period. Because of the successively increasing delays pro a full zone period beginning three-eighths of a zone period after the output of the matrix is energized, etc.; and solenoid 70a becomes energized for a full zone period beginning at a time one full zone period after the input to the delay 90a becomes energized. The effect of these delay devices on the leading vertical line of the printed character A may be seen in FIGURE 3b.

Each of the other signals applied to these delay means is similarly delayed, and the trailing edge of the character A is parallel to the leading edge or stroke of the printed character. As clearly shown in FIGURE 3b, the character A is printed in italic form as a result of the delay devices aforementioned.

When it is desired to print a character in bold face, solenoid 88 is energized to by-pass the delay means 90a 9011, and solenoid 80 is energized to connect the oneshots 101a-10lg in the input circuitry to the encoder 66. In the embodiment of FIGURE 4, each of these one-shots 101a-101g preferably produces an output pulse, when triggered, of the same Width or duration, and the duration of these output pulses is slightly greater than the duration of the output pulses produced by the first set of one-shots 68a68g. By way of example only, the oneshots 101a-101g may be selected to provide pulses having a duration equal to 1.25 times the zone period, i.e., the duration of an output pulse from any of the oneshots 68a-68g. Since the width of a printed line or mark is determined by the duration for which a printer solenoid is energized, and since the duration for which the solenoids 70:1-701' are energized is deter-mined by the width of the input pulse to the encoder 66, it can be seen that the effect of inserting the one-shots 101a-101g is to produce printed marks of greater width than those which occur when the one-shots 82a-82g are employed.

Considering that the letter A is to be printed, solenoids 70a-70g are energized during the first zone of printing. Since the duration of this printing zone now is determined by one-shot 101a, and since this device produces a pulse having a width 1.25 times the normal zone period, it can be seen that the width of the leading stroke of the printed character A (FIGURE 30) is a vertical line 1.25 times the width of a regularly printed A (FIGURE 3a). Each of the other lines in the other zones similarly has a greater length or duration. However, since the outputs of the one-shots l01a-101g overlap one another, each printed mark begins at the start of its normal zone period. Thus, the vertical stroke at the trailing edge of the printed character A begins at the start of the fifth zone, just as in the case of a regular character. The width of this stroke, however, is greater than the width of the character printed in regular form, it being 1.25 times the normal zone period.

The small incremental increase in the width of the input pulses to the encoder 66, introduced by the one-shots Mia-101g, is sufficient to result in the printing of a bold face character without any significant effect in the shape or the appearance of the printed character portion in zones, b, c and d, at least for most of the printed characters.

In practice, it is not necessary to provide two separate sets of one-shots 101a-101g and 82a-82g, as in FIGURE 4. All that is necessary is that some means he provided for increasing the output pulse width of each one-shot. One way in which this may be done is illustrated in FIGURE 5. As shown there, the switch arm 78a connects either a capacitor 94 or a capacitor 96 in the oneshot 82a. These capacitors may be connected in the time constant circuit of the one-shot 82a to determine the out put pulse width. Capacitor 94 may be used for regular printing, and capacitor 96 may be used for bold face printing. In this event, capacitor 96 is chosen to be larger than capacitor 94. The other oneshots 82b82g may be arranged in a similar manner.

There has thus been illustrated and described apparatus for printing characters, such as letters, numbers,

etc. in either regular, italics or bold face Without requiring any change in the encoder or the digital input signals thereto.

What is claimed is:

1. In a matrix printer, the combination comprising:

a set of M printer elements, each for printing a different portion of a character;

a separate actuating means for each of said printer elements;

character print signal producing means having M output lines, one for each said actuating means;

a first set of coupling means for coupling each of the output print signals on said M lines to the respective actuating means with substantially the same time delay;

a second set of coupling means for coupling each of said output print signals to the respective actuating means, each different coupling means of said second set providing a different time delay; and

means for applying said output print signals to either one of said first set of coupling means and said second set of coupling means selectively.

2. The combination as claimed in claim 1, wherein the progressively differing delays provided by the different ones of said second set of means differ from one another according to an arithmetic progression.

3. The combination as claimed in claim 1, wherein the last-mentioned means is a set of switches, and wherein in one position of the switches the output print signals are applied to said first set of coupling means, and wherein in another position of the switches the output print signals are applied to the said second set of coupling means.

4. The combination as claimed in claim 1, wherein a character is normally formed on a document by printing marks at selected ones of M rows in N successively printed columns, said M printer elements being arranged side-byside on one side of a document printing zone at locations to print the M rows of marks, respectively; an anvil disposed opposite said printer elements on the other side of said zone; and means for moving one of said anvil and said set of printer elements relative to the other in a direction from one end of the printing Zone to the other end.

5. The combination as claimed in claim 4, wherein said set of printer elements is a set of elongated print bars arrayed in parallel, side-by-side relation, each of said print bars extending the length of said printng zone, and wherein said anvil extends across the width of the arrayed bars and is moved at constant speed, during a printing operation, from one end of the print bars to the other end.

6. In a matrix printer, wherein a character normally is formed on a document by printing marks on selected ones of M rows in N successively printed columns, the combination comprising:

a set of M printer elements arranged side-by-side to print the M rows of marks;

a separate actuating means for each of said printer elements;

signal producing means having M output lines, one for each said actuating means, on which output print signals for controlling the printing of marks in the M rows of a column appear concurrently; and

means for controlling the operation of said signal producing means selectively to produce output print signals having either one of a first or a second duration.

7. The combination as claimed in claim 6, wherein said signal producing means produces the print signals for successive ones of the N columns of a printed character in succession in response to successive clock pulses applied to the signal producing means, and wherein said controlling means comprises means for selectively controlling the durations of said clock pulses to have either one of said first or said second duration.

8. The combination as claimed in claim 7, wherein said signal producing means is a matrix encoder.

9. The combination as claimed in claim 7, wherein said M printer elements are located on one side of a document printing zone, and including: an anvil disposed opposite said printer elements on the other side of the printing zone; and means for moving one of said anvil and said set of printer elements relative to the other in a direction from one end of the printing zone to the other end.

10. The combination as claimed in claim 9, wherein the set of printer elements is a set of elongated print bars in parallel, side-by-side relation, each of the print bars extending the length of the printing zone, and wherein the anvil is moved at constant speed, during a printing 7 UNITED STATES PATENTS 2,457,133 12/1948 Delorajne 178--30 2,976,801 3/1964 Dirks 1971 X 3,157,456 11/1964 Kirkuchi 346-78 3,209,681 10/1965 Sanborn 10193 3,223,029 12/1965 Simshauser 101-93 3,267,845 8/1966 Simshauser 101-93 WILLIAM B. PENN, Primary Examiner. 

1. IN A MATRIX PRINTER, THE COMBINATION COMPRISING: A SET OF M PRINTER ELEMENTS, EACH FOR PRINTING A DIFFERENT PORTION OF A CHARACTER; A SEPARATE ACTUATING MEANS FOR EACH OF SAID PRINTER ELEMENTS; CHARACTER PRINT SIGNAL PRODUCING MEANS HAVING M OUTPUT LINES, ONE FOR EACH SAID ACTUATING MEANS; A FIRST SET OF COUPLING MEANS FOR COUPLING EACH OF THE OUTPUT PRINT SIGNALS ON SAID M LINES TO THE RESPECTIVE ACTUATING MEANS WITH SUBSTANTIALLY THE SAME TIME DELAY; 